ELVING: Paul Ryan has been serving in the House of Representatives since 1998. He's in his seventh term. But the reason everyone knows his name who knows his name is that he is the chairman of the House Budget Committee, and he has been putting forward for some years now - but now as House Budget Committee Chairman with some authority - a budget proposal, a plan for how to change the spending and taxing policies of the United States, and eventually balance the budget - not for a couple of decades, but eventually do it, and do it through a program of tax cuts and also program cuts, including great constraints on the spending we do for Medicare and Social Security. In other words: a controversial budget plan, one that has been highly energizing to conservatives and anathema to liberals.

WERTHEIMER: Well, I would say probably also highly energizing to liberals.

ELVING: It has been energizing on both sides. As we were saying a moment ago, this is the kind of pick that really says game on. It doesn't just hit the reset button. Doesn't just say, let's change the subject in this campaign. It says, let's go rumble.

WERTHEIMER: Let's listen to a little bit of the kinds of things that Mr. Ryan says when he's speaking out. This was part of the Republican response to the State of the Union.

(SOUNDBITE OF SPEECH)

REPRESENTATIVE PAUL RYAN: We believe as our founders did, that the pursuit of happiness depends on individual liberty, and individual liberty requires limited government. Limited government also means effective government. When government takes on too many tasks, it usually doesn't do any of them very well. It's no coincidence that trust in government is at an all-time low now that the size of government is at an all-time high.

WERTHEIMER: So what do you think it means that Mister Romney has picked a small-government guy to run with on this election?

ELVING: It means that Mitt Romney has decided that he has still to consolidate his conservative base going into the November election. At one time, most observers agreed, Mitt Romney thought his problems on the right were in the primaries. And once he had secured his nomination - which he did around March-April - that he could then begin to tack toward the center.

His own campaign director at point referred to it as hitting the Etch-a-Sketch and starting over with a blank slate, and presenting himself to the country as more of a centrist. Now we see that that is not going to be possible for Mitt Romney - either because of the way they've been reading the polls, or because of the flak they've been taking from the right, they have decided that they need to go back to the base and secure that going into the fall, especially as we approach their convention later this month.

WERTHEIMER: So, Ron, do you take this as an endorsement of the kinds of things that Ryan has been talking about? I mean, it would - the vice president doesn't generally get to lead on issues. He gets to follow.

ELVING: Let's be clear. Paul Ryan's budget was already embraced by Mitt Romney earlier this year. He said he liked the Paul Ryan budget concept, and that he wanted to go in that direction. So, in a sense, it was already owned by Mitt Romney. But this is much more powerful. To put this voice, to put this personality, to put this symbol on the ticket is going to make this not just the Romney-Ryan ticket - as you said a moment ago, and you said a mouthful saying those two names together.

It's going to be, for a lot of people, the Ryan-Romney ticket. And that includes a lot of the conservative media who have been pushing Paul Ryan, especially over the last week or so.

WERTHEIMER: Don, how much do we know about the relationship between these two men?

GONYEA: They seem to be very close. It's not clear how much time they have spent together. But when Governor Romney was bouncing around the country, from primary to primary, he finally got to Wisconsin when Rick Santorum was his primary remaining rival at that point. And Paul Ryan both endorsed him and campaigned with him. And I was with him up in Appleton and at the Serb American Hall Friday Fish Fry, outside Milwaukee. And they kind of looked like bookends, but father and son.

I mean, it has been noted that Paul Ryan does look like the sixth Romney son. And actually, he's about the same age as Romney's oldest son. And I can tell you, it was probably the most comfortable I had ever seen Mitt Romney. He really felt - it looked like he felt good standing next to Paul Ryan.

WERTHEIMER: Well, now that obviously is one of the big advantages of picking Ryan. But what about other advantages?

GONYEA: Well, it does send that message to the base that Ron was talking about. There are still a lot of Romney skeptics out there among Republicans. And you even go to a Romney rally - you go Romney rally in Michigan, the state where he was born, and walk up to people and start talking to them, and as often as not, the first thing out of their mouth is: Well, I was a Rick Santorum supporter, but I guess Romney's the guy now.

So he clearly needed to shore that up. And Paul Ryan sends the message that when Mitt Romney talks about embracing the Ryan plan, that it's not lip service. There's been no indication that Mitt Romney has been tacking back to the center, as candidates usually do once they secure the nomination. But the sends a pretty clear message that he won't be and really that he can't, at this point.

WERTHEIMER: Do you see a downside?

GONYEA: We've never seen Paul Ryan campaign, even statewide, let alone around the country. He's going to get a lot of scrutiny. And the downside is that he's probably the first choice of many Democrats, as well. They are really anxious to take this Ryan plan to Florida and Ohio and Michigan and talk about the Medicare and the Medicaid and the Social Security aspects of it.

WERTHEIMER: What do you think, Ron, about what this choice will do to the race?

ELVING: I do think it adds a great deal of excitement and energy. I do think it adds youth, and youth was something that this ticket was going to be in need of. One of the advantages of Marco Rubio - the senator from Florida, who, of course, speaks Spanish and comes from Florida - he was only 40 years old. And I think that this is something that this ticket really needs.

WERTHEIMER: And Paul Ryan is only 42 years old.

That's NPR's Ron Elving and Don Gonyea. Thank you both.

GONYEA: Thank you.

WERTHEIMER: We're following the top story in politics. This hour, Wisconsin Congressman Paul Ryan is Mitt Romney's choice for vice president. We'll be following this story throughout the program and online at npr.org. Transcript provided by NPR, Copyright National Public Radio.